docs: def shutdown(self):
          """
          Shutdown factory.
  
          This is shutting down all created connections
          and terminating ZeroMQ context. Also cleans up
          Twisted reactor.
          """
          for connection in self.connections.copy():
              connection.shutdown()
  
          self.connections = None
  
          self.context.term()
          self.context = None
          if self.trigger:
              try:
                  self.reactor.removeSystemEventTrigger(self.trigger)
              except Exception:
                  pass